US 6,476,664 B2Granted

Integrated device with voltage selector

AssigneeSTMicroelectronics S.r.l.

InventorsPaolo Rolandi, Massimo Montanaro, Giorgio Oddone

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Abstract

The integrated device comprises a PMOS transistor and a voltage selector having an output connected to the bulk terminal of the PMOS transistor. The voltage selector comprises an input stage supplying a supply voltage or a programming voltage according to whether the device is in a reading step or in a programming step; a comparator connected to the output of the input stage, receiving a boosted voltage, and generating a first control signal, the state whereof depends upon the comparison of the voltages at the inputs of the comparator; a logic circuit connected to the output of the comparator and generating a second control signal, the state whereof depends upon the state of the first control signal and of a third-level signal; and a switching circuit controlled by the first control signal, by the second control signal, and by the third-level signal and supplying each time the highest among the supply voltage, the boosted voltage, and the programming voltage.

Claims17

Dependent claims

An integrated device comprising:

a switching element having a bulk terminal;
and
a voltage selector circuit that includes:
first and second selector inputs, receiving a first and a second voltage, respectively;
an output connected to said bulk terminal of said switching element;
an input stage having a first voltage input and a second voltage input, a control input, and an output, said first and second voltage inputs being connected to said first and second selector inputs of said voltage-selector circuit, respectively, and said control input receiving a first operative condition signal to control selective connection of one of said first and second voltage inputs to said output;
a comparator having a first input connected to said output of said input stage, a second input receiving a third voltage, and an output generating a first control signal having a first level when said first input is at a higher voltage than said second input and having a second level when said second input is at a higher voltage than said first input;
a logic circuit receiving said first control signal and a second operative condition signal, said logic circuit generating a second control signal having a first level when said first control signal has said second level and when said second operative condition signal has a preset level;
and
a switching circuit receiving said first voltage, said second voltage and said third voltage, said first control signal and second control signal, as well as said second operative condition signal, said switching circuit having an own output connected to said output of said voltage-selector circuit and supplying, on said own output, said second voltage in presence of said first level of said second control signal, said first voltage in presence of said preset level of said second operative condition signal, and said third voltage in presence of said first level of said first control signal.

7 more elements

A voltage selector circuit comprising:

first and second input terminals;
an output terminal;
an input circuit having first and second inputs that are coupled to the first and the second input terminals, respectively, and having a first control input, and an output;
a comparator circuit having first and second comparator inputs, and a comparator output, the first comparator input coupled to the output of the input circuit, the second comparator input coupled to a third input terminal;
a logic circuit having first and second logic inputs and a logic output, the first logic input coupled to the comparator output, the second logic input coupled to a second control input;
and
a switching circuit having a first switching input coupled to the first input terminal, a second switching input coupled to the second input terminal, a third switching input coupled to the third input terminal, a fourth switching input coupled to the comparator output, a fifth switching input coupled to the logic output, a sixth switching input coupled to the second control input, and a switching output coupled to the output terminal.

4 more elements

Dependencies are inferred from the claim text.